Electbic-besistance tuenace



Dec. 11, 1923. v 1,477,384

T. A. REID L ELECTRIC RES I STANCE FURNACE Filed Feb. 25, 1922 /9 29 a@ a7 a6 a9 /7 /9 WITNESSES.' INVENTOR M n AT ORN'EY Patented Dec.. 11,1923.

UNITED STATES 'PiffEwema; if

THOMAS A. REID, or WIEKINSBRG, PENNSYLVANIA, AssIGNoR: TowEsTINdHoUsE ELECTRIC a MANUFACTURING CoMPANr, A CoRroRATIoNoF PENNSYQIxvANIA'.` j

ELECTRIC4REsIsTANCE EURNACEL- Application filed February 23, 1922. SeralNo. 538,541.'

To all whom z't may Concern: V Be it` known'that I, THOMAS A. REID, a citizen of the United States, and a .resident 4of Wilkinsburg, in the county of Allegheny Y and -State of Pennsylvania, have invented a new and useful Improvement in Electric Resistance Furnaces, of which the `following is a specification. i .v

My invention relates to electric furnaces and particularly toelectric resistance furnaces and it has foritslobject to'providc a relatively simple .structure for relatively small electric resistance furnaces, comprising a relatively small number of relatively large shaped parts to permit of easilyl and quickly assembling and disassembling the entire furnace.

\ In practising my invention, I- provide an open-end and open-top thin Sheet metal casing and a thin sheet metal top plate having reinforcing sidemembersu Iprovide a plurality of blocks of refractory fmaterial placed inside of vsaid open-ended casingin a predetermined order and soshaped and placed as to provide a furnace chamber; 4I provide a plurality of relatively thin' refractory plates each having a plurality of small spaced-apart, alined, integral projec` tions on one surface thereof, to'constitute the lining of the furnace chamber, and a resistor member operatively engaging-that side of the refractory plate on whichy the small, integral projections are located. I provide further a front and a rear `metal plate having embodying means for operatively engaging and interlocking with the front and rear edges of the casing) and of the top plate and a plurality of olts located in the corners of the metal` casing for clamping the front and the rear plates against the casing and the to-pplate, and for holding the refractory blocks in proper operative position longitudinally of said casing. The front plate is provided with an opening through which the thin refrac tory plates and the resistor may be placed in proper operative position in the furnace structure and heat insulating platesy are locatedback ofv the front plate to maintain the thin refractory plates in their roper operative positionl longitudinally o said furnace chamber;

In the singlesheetof drawings,

Figure L1 is a` view,l in `vertical lateral cross-section, of "an .electric 4resistance furnace embodying `my invention, Vand illus- `trated as located on an assemblingy fixture.

mso

\ Fig. 2 is a vertical longitudinal-,section of "if a furnace embodying my invention, taken on theline. IIe-II -of Fig. 3;- Y Fig. 3 is a front view of afurnacemembodying my invention, and

Fig. 4 is a partial.y sectional viewthereof taken on line IV-IVOf Fig. 3. x l

An `electric `fur-nace, designated generally by the numeral 11, 4comprises a thin sheet metal casing 12" having openV ends andbent to substantially .U-shape. In order to maintain the casing 12 in its preformedfshap'e during the process of-assembly of the furnace, it may be placed upon a fixture comprising a substantially horizontally Lextending bench or platform 13, upon:l which are placed twojaws orclanips 14 which may be either adjustably located' thereon by `any suitable' means or may be provided with adjusting means comprising a substantially stationary block lsecured to the topVof the -f platform 13 and an adjustingscrew $16,the inner end ofwhich bears againstfthe outer surface of 'one of the jaws` or' clampsy 14. This construction of the assembly i fixture a lnumber of different widths loffuI-nace cas- After the open-ended fand' '.f open-topped casing 12 is located between the adjustable jaws 14C, two longitudinally extending clamping rods 17 are placedin the cornersof the casingi lAfrefractory brick or block 18 of its lower corner portions cut awayvto propermits of employing the same `fixture for ""2 a suitable heat insulating material, having vide chambers 19 in which the rods 17 vmay fit, is placed upon the bottom of thefcasing 12, its width being such as to t'closelybe tweenV the sidesV of the casing; Then, two i side blocks-21and 22,0f substantially the` same materialas theblock `18, kare placed on v edge upon the member 18 with theirouter surfaces vengaging theV respective' inner's'urfaces of the' sidesof the Casin' 12. Abrick j or block 23 of a suitable hig #temperature resisting refractory mat'erial is next lplaced i upon the bloclr18v and between .the blocks 21 and 22, and blocks 24 and25v ofvsimilarrefracto-ry material are placed `oni edge upon j the block 23 and inside of the blocks 21 and stantially the same material as the blocks 23, 21 and 25,., isY placed flat-wise on the upper edges-of Vthe blocks 21 and 25, the block 26 being of such width as to fit closely between the inner surface `of the .blocks 21 and 22, and v'of such thickness as to bring its upper sur face in substantially the -same plane as the upper edges of the blocks 21 and 22. A block 27, substantially the same in material and dimensions as the block 18, is then placed upon the block 26 and the upper edges of the blocks 21 and 22, the blocks 27 being of such thickness fas to bring its upper surface substantially .flush with the upper edge of the sides of the casing 12. Two rods 17 are placed .in chambers 19 provided in the upper corners of the :block 27 substantially ashereinbefore described in connection with the block 18. The longitudinal position of lall .of the `blocks is substantially as indicated in Fig. 2 of the drawing, there being a space leftbetween the rear end of the lblocks 23, 21, 125.-:and216 and 'the :rear vedge of `t-he'casing and a relatively .smaller space left between the blocks .18, 21, l22 and 27 andthe rear edge of the casing. A top plate 28 of thin sheet metal having reinforcing. members 29, of substantially L-shapein lateral cross-section secured thereto at its sides, is `placed upon the block 27,.the downwardly extending portions of the `members 29, being located outside of,-serving to hold the upper edges of the sides of the casi-ng 12 in proper operative position.

A block-30 of a suitable high'temperature resistingrefractolry material .is placed in its proper operative position with the inner face rthereof inabutting relation to the rear end surfaces of the blocks 23, 21, 25 and 26, the block 30 being-olf such thickness-that its rearasurface is :substantially flush with the rear edge of the blocks 18, 21, 22 and 27, as liliustratedi'in Fig. 2 ofthe-drawing. l A-rela tivelythin '.p'late 31 of a 1refractory heat-insulating/material, .or of asbestos lumber, is then i vplaced i in @position fabutting not only against the rearlportionsofthe plates 18, 21,

22 and 27, `butf also against the :rear surface of the plate 30.y The thickness of lthe plate 31 is suchas-to bring its @rear surface ysubstantially iiush :withthe rear edge of the casing 12 :and of the -top'plate 28.

A rear end plate :32, havingan opening 32=L therethrough, is placed 4in its proper operative position :against :the 4outer rsurface of the plate 31, 'its'.other dimensions being such as to cause it to lfit closely within the metal casing. The plate 32.has an inwardly e-X- tending flangeor :bead I33located in such vposition thereon as yto :lie outside of the edge of the :casing 12 and of 'thetop plate 28, to thereby retain these 'relatively thin -sheet metal members in their proper voperative positionrelatively close against'the outer surfaces of the Fblocks 18, 21, 22 and27. A front 4plate 31 is then placed in its proper opera'- tive position -at the front of the furnace structure with its inner face abutting against the front end surfaces of the hereinbefore mentioned longitudinally extending refractory bricks or blocks. The front plate is provided with an outer flange 35 'and an inner flange or bead 38, to be located respectively on the outside and on the inside of the sheet metal casing 12 and of the top plate 28 at the front ends thereof, to securely hold them in their proper operative positions relatively to the outer set of refractory blocks hereinbefore described; :Nuts 37 may be screwed upon the threaded outer end portions at the front and at the rear of the rods 17 to securely clamp the front and rear end plates, not only against the casing 12 andy the top plate 28, but also against the lrefractory blocks hereinbefore described. After the nuts. 37

have lbeen tightened on the rods 17, the furnace structure is substantially self-supporting and may be removed from the assembling fixture hereinbefore described, if desired. The front .plate 31 is Aprovided with a substantially rectangular opening 38 substantially coeXtensive with, in outline, the lateral dimensions of a furnace chamber 39 constituted by the refractory bricks or blocks assembled as hereinbefore described.

In order to provide a removable muflie or lining for the furnace chamber, as well as a resistor-supporting means, I place a plurality of relatively thin refractory plates 11 in spaced-apart relation in the furnace chamber 39, each plate having a plurality of relatively small spaced-apart, alined, integral projections 12 on one surface thereof. These plates may be provided with shouldered edge. portions, substantially as illustrated in F ig. 1 of the drawing, to permit of interlocking the same to maintain them in :their proper yoperative position within the furnace chamber, although this feature is not an essential one and any Vsuitable method may be 4employed for maintaining them invtheir :proper operati-vexposition within the furnace chamber. A resistor member 13 operatively engages that surface of the plates 11 having the integral projections and may comprise any `suitable or desired form of vmetallic resister member Iof such resistance Ithat the length of resistor memberemployed will permit that amount of current to iiow which is necessary to heat the chamber to a predetermined temperature when the ends 11 of the resistor are connected to a suitable source of supply (not shown). Any desired method of bringing -out the ends 11 through openings .15` inthe furnace structure .may be em-v ployed. Any suitable or ldesired interconnection of the Yvarious resistor ymembers 13, located at the bottom, side and'top ofthe furnace chamber may be employed. .The thin refractory plates and the coi-operating resistor member are more particularly described and claimed in application Serial No. 449,685, filed March 5, 1921, by O. A. Colby and myself and assigned to the Westinghouse Electric & Manufacturing Company, to which reference may be had for further details. l l f A rectangular block 46 of asbestos lumber is placed immediately in front of the block 26 and back of the front plate 34, the lower edge of the plate 46 being immediately in tom plates 41; The front plate 34 is provided with a forwardly projecting ledge or shelf 49, the top of which is a relatively small distance below the bottom of the refractory plate 41 constituting the bottom lining of the furnace chamber, and has lo.- cated thereon a horizontally extending plate 51 of asbestos lumber, suitably secured thereto by means of bolts 52.

Vertically extending outside members 53 y are bolted against the front plate 34 immediately adjacent to the sides ofthe furnace chamber 39 by a plurality of bolts 54, each member 53 having an inner offset or shoulder portion 55 to provide ay guidejfor a door 56 comprising a metallic casing 57 which is filled with, or which has its inner surface lined with, a plurality ofI bricks or slabs 58 of a. suitable refractory material. A sight opening 59 is provided in the door member 56, normally closed by a cover member 61 loosely secured on the casing 57. A bracket 62 may be secured against the front plate 34 at one side thereof upon which may be mounted any suitable or desired mechanism. which is operative to permit of raising and lowering the door 56 from its normal operative position illustrated in Fig. 3 of the drawing to permit of placing material within and removing it from, the furnace chamber 39.

If it becomes necessary to remove the resistor member 43 because of damage thereto or to remove one of the plates 41, it is only necessary to remove the late 51, the plate 48, the plates 47 and the p ate 46, after which any or all of the plates 41 may be removed from the furnace chamber 39 through the opening 38 in the front plate, it being understood, of course, that the door 56 has been moved upwardly or taken off entirely.

The hereinbefore described construction and method of assembling provides anelecytric resistance furnace comprising relatively few parts which are assembled in predetermined order and which may, `thereforebe assembledI and disassembled iirrelatively short periods of- `time. and which structure is provided with means for securely interlocking the various parts thereof iny such manner that a relatively compact furnace structure is obtained, the parts 'of which shall, at the same time,vmaintain`their proper operative positions during .the operation of the furnace and shall also permit of shipping the complete furnace without danger of damage thereto. u' i Various modifications lmaybe made inthe device embodying my invention without de.- parting fromthe spirit and scope thereof and I desire that only such limitations shall be placed thereon as` are imposed bythe prior art or are specifically set forth in the appended claims.

I claim as my invention: 1- y 1. An electric furnace structure comprising an open ended and open top metallic casing, a removable metallic top `plate for said casing interlocked therewith, an 'outer base plate, two Aspaced apart `outer side plates, and an outer to-p plate inside of said metallic casing, all `of said plates being of refractory heat-insulating` material, an inner base plate, a pair `of spaced-apart"inner side platesand an inner top plate, all located inside of vsaid heat-insulating `-plates and comprisingrefractoiy high-temperature resisting material, and spaced apart to provide a furnace chamberand a heating element for said furnace chamber comprising a `plurality of' relatively thin i refractory plates constituting a lining for .said furnace chamber and a resistor member heldfin properoperative position in said `furnace structure by said 'thinlrefractory' plates in co-operation with the plates constituting the inn er lining.

`2. An electric furnace structure comprising an open ended and open top metallic casing, a removable metallic top plate yfor said casing interlocked therewith, an outer` rality of relatively thin refractory plates.

constituting a muifle or lining for said furnace chamber, a resistor member held 1n proper operative 4position in said furnace structure by said thin refractory plates vin co-operation with the plates vconstituting the spaced-apart iny inner lining, vand front and rear metallic end `plates interlocked with said metallic casin and casing top.

. 3. "n electric furnace structure comprising an `open ended and open vtop metallic casing, a removable metallic top plate for said casing interlocked therewith, an-outer b'ase'fp'late, two spaced apart outer side plates and anouter top plate inside of said metallic casing, all of said plates being of refractory `heat-insulating material, an inner base plate, a pair of spaced-apart inner side plates and an inner top plate, all located inside of said heat-insulating plates and comprising'refractory high-temperature resisting material, and spacedapart to proyide a furnace4 chamber, a heating element for said furnace chamber comprising a plurality of relatively thin refractory plates constituting a `Inutile for said rfurnace chamber and a resistor member )held inprop'er operative position in said furnace struc'- ture by said thin refractory plates in cooperation with the plates constituting the inner lining, front andvrear end plates interlocked with said metallic casing and casing top, and a plurality of bolts for holding said end Aplates against the end of said casing, 'casing top and `said inner and outer base, side and :top plates.

4. In a quickly mountable and demountable furnace structure, in combination, an open end 'and open top metallic casing, an outer-and an inner lrefractory base plate located on the bottom of said casing, spacedapart'outer and inner refractory side plates supported'respectively by the outer and inner base plates, outer and inner refractory top plates supported respectively by the outer and inner spaced-apart side plates, a metallic top plate supported by and interlocked with the sides of they metallic casi ing, front and rear end plates interlocked with fthe casing and-casing top, and 'a plurality of bo-lts'for 'clamping said Afront and rea-rend plates'against said casing-and casing top, said bolts being maintained in', spaced-'apart relation in said metallic. casing by said refractory outer base and top plates. y

5. In a quickly mountable and demountable `furnace structure, in combination, an open-end and open top lmetallic casing, an outer and an inner refractory base plate located on the bottom of said casing,` spaced apart outer and inner refractory side plates supported -respectiyely by the outer and inner base plates, outer and inner refractory top plates ysupported respectively by t-he outer and inner spaced-apart side plfates`,a nietallictop plate supported-by and interlocked with the Vsides of the metallic casing, front and rear end lplates interlocked with the casing and casing top, 4a plurality of bolts for clamping rsaid vfront and rear .end plates against said casing and casina "top, said bolts being maintained in space@ -apart relation in said metallic casing by said refractory outer base and'top plates, a plurality of relatively thin -refractory plates constituting the Inutile of the furnace chamberlocated inside of said inner refractoryplates and l'supported by said inner base plate, and a pluralityof refractory heat :insulating plates located between said front endjplate and said thin refractory plates for maintaining said thin refractory platesY in yproper operative position longitudinally of said furnace.

Iny testimony whereof, )I 'have "hereunto subscribed ymy name this 20th d'ay of `F ebruary 1922.

THOMAS A. REID. 

